Qantas chief apologises for flight problems

In a message emailed to Frequent Flyer members, Mr Joyce sought to allay "any perceptions" that safety standards had slipped.

"You may have been affected directly or indirectly by the disruptions, or seen the intense media coverage and widespread speculation about Qantas safety and maintenance standards," Mr Joyce said.

"First, let me say how very sorry I am if you were affected personally by the disruptions.

"I sincerely regret any frustration and anxiety you may have experienced due to the delays. Some of you were disappointed in us

and we were disappointed in what happened," Mr Joyce said.

The run of incidents started on March 30 when a Boeing 747, QF5 from Sydney to Singapore, was forced to return after take-off after a surge from one of the engines forced pilots to shut it down and return.

The next day, an Airbus A380, flight QF32 from Singapore to Sydney, landed in a shower of sparks when two tyres burst on landing.

On Easter Monday, air crew on another Boeing 747 operating as QF93 from Melbourne to Los Angeles, noticed a crack in a window pane in the cockpit, which needed replacement, causing delay.

The next day, another Boeing 747, QF1 from Bangkok to London, suffered an engine surge. The engine had to be shut down and the flight returned to Bangkok.

"These were mechanical issues: at no time did they represent safety threats," Mr Joyce said.

On the engine surges, it was a question of "performance, not of safety", as the Jumbos are designed to fly on three engines safely, he said, adding that Qantas was working with Rolls-Royce to eliminate the problem with the engine from its fleet.

On the Airbus tyre blowouts, Mr Joyce said television images showed "apparent sparks flying" but the two tyres that failed were two of 20 on the aircraft and "at no stage was safety ... compromised".

And it was "not unusual for aircraft window panes to experience chipping and cracking", he said.

Other recent technical problems not mentioned in Mr Joyce's apology include a wiring problem on the QF5 plane that delayed its reintroduction to service Brisbane to Los Angeles; a flap warning during pre-landing checks on QF779 Sydney to Canberra on Tuesday; and a landing-gear fault warning on a 767, QF485 from Melbourne to Perth, on Wednesday.

Mr Joyce reasserted that "safety comes first for Qantas", after the professional engineers' union claimed that "details of key safety aircraft incidents over the past weeks have not been referred to senior engineers at Qantas".

Qantas has been locked in a bitter dispute with members of the professional engineers union, who since November have imposed overtime bans on certifying airworthiness of aircraft repairs. Qantas has been using its qualified managers to perform the role instead.

"Let me vigorously counter any perception that Qantas is lowering its maintenance standards, or moving maintenance offshore, or that management is failing to listen to workers' concerns about safety," Mr Joyce said.

"This would be simply untrue and damaging to our reputation, as well as unnecessarily concerning to you, and all our customers. I can assure you that our commitment to safety, and our investment in the very best aircraft and engineering and maintenance, is as strong as it has ever been."

Qantas puts safety before schedule, he said.

"But our commitment to safety means that sometimes, regrettably, there are delays to our schedule. I can't promise to eliminate delays altogether, but I can promise that we will always do all we can to care for our customers if delays occur," he said.

Mr Joyce's apology came just hours after he announced a heavy maintenance base located in Brisbane would start work on Airbus A330 planes, with 21 new apprentice engineers to join the 450-strong workforce there.

Qantas employs 5500 people in its Australian-based engineering workforce, which undertakes 90 per cent of aircraft heavy maintenance, the airline said in a statement.

"Any work that is carried out offshore is overflow work or work undertaken in major operational hubs due to regulatory requirements that aircraft undergo specific certifications before operating a long-haul service. Any overseas maintenance work is overseen by Qantas engineers and certified to Civil Aviation Safety Authority standards," the airline said.